Why do some names appear with a bubble in a Contact List column and other names do not

I have a sheet with a Contact List column type called Task Owner. I also have Summary fields set up that are Contact List types. The Task Owner fields are formulas to pull from one or more of the Summary fields.

Example: Row 1 has a Task Name, Task Owner, Status, % Complete, Start Date, End Date, etc.

The Task Owner field for Row 1 =[Security Analyst 1]# ; where Security Analyst 1 is a Summary Sheet field that is a Contact List. When I select a Contact Name in the Security Analyst 1 field, it will populate the Task Owner on Row 1, but it just lists the contact's name and does not show the bubble with the contact's initials. (Seems like it is not recognizing it as a contact with an associated email address). Sometimes it works and other times it does not. See attached. It works for Troy but not for Stacey.

Note: Stacey is a licensed user within our company's enterprise org structure and troy is not.

This is hindering the ability for Stacey to see their assigned tasks when we create a report that filters on Current User. Stacey does not see anything, but Troy does.